Debt, net of unamortized deferred financing cost - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands							3 Months Ended		9 Months Ended		12 Months Ended
	May 13, 2025	Apr. 30, 2025	Dec. 19, 2024	Jul. 31, 2024	Feb. 22, 2024	Jan. 03, 2023	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Nov. 10, 2023
Debt Instrument [Line Items]
Proceeds from issuance of preferred stock and Constellation Warrants									$ 18,471	$ 305,340
Preferred stock tranche liability, at fair value							$ 1,650		1,650		$ 3,940
Gain (loss) on preferred stock tranche liability							$ 500	$ 1,140	2,290	1,140
Repayments of debt									$ 164	$ 89,862
Allianz Strategic Investments S.à.r.l. (“Allianz”) | Series A Preferred Stock | Allianz Investment Agreement
Debt Instrument [Line Items]
Preferred stock, dividend rate, per-dollar amount (in dollars per share)	$ 1,000			$ 1,000
Proceeds from issuance of preferred stock and Constellation Warrants	$ 18,500
Allianz Strategic Investments S.à.r.l. (“Allianz”) | Allianz Tranche Right | Series A Preferred Stock | Allianz Investment Agreement
Debt Instrument [Line Items]
Number of securities called by warrants or rights (in shares)	18,471				50,000		1,523,289		1,523,289
Preferred stock, dividend rate, per-dollar amount (in dollars per share)					$ 1,000
Line of Credit
Debt Instrument [Line Items]
Outstanding principal amount							$ 586		$ 586		0
Repayments of debt			$ 133,400
Write-off of deferred issuance costs											4,500
Credit Facility | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 250,000
Secured Debt | Credit Facility | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 100,000
Secured Debt | Credit Facility | Line of Credit | Minimum | Base rate
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)						1.00%
Secured Debt | Credit Facility | Line of Credit | Minimum | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)						2.00%
Secured Debt | Credit Facility | Line of Credit | Maximum | Base rate
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)						2.00%
Secured Debt | Credit Facility | Line of Credit | Maximum | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate (in percent)						3.00%
Secured Debt | Kontora Credit Facility | Line of Credit
Debt Instrument [Line Items]
Outstanding principal amount		$ 600					$ 586		$ 586		$ 0
Fixed quarterly installments		$ 100
Interest rate (in percent)		6.70%
Economic equity required		$ 1,800
Economic equity required (in percent)		30.00%
Revolving Credit Facility | Credit Facility | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 150,000						$ 110,000
Accordion option, additional borrowing capacity						75,000
Accordion feature, maximum borrowing capacity						$ 225,000